CALL FOR PROPOSALS

                          GLOBAL 3mm VLBI ARRAY

                        Deadline:  1 February 2021

        VLBI proposals for observing at 3mm wavelength (86 GHz) using:

         the VLBA,  GBT*,  EFFELSBERG,  PICO VELETA,  NOEMA,  ONSALA,  

         METSAEHOVI, YEBES  and  KVN  telescopes should be submitted by

                        1 FEBRUARY 2021 (UT 22:00)

                        ==========================

     Successful proposals will be considered for scheduling in GMVA

     Session II 2021 (30 September - 4 October) or in a later session.

       *  SEE ALSO THE SECTION BELOW REGARDING PROPOSALS FOR GMVA

       *  OBSERVATIONS TOGETHER WITH PHASED-ALMA IN ALMA CYCLE 8

              =============================================

              |                                           |

              | ALL PROPOSALS SHOULD BE SUBMITTED USING   |

              |                                           |

              | THE NRAO PROPOSAL SUBMISSION TOOL (PST):  |

              |                                           |

              |           https://my.nrao.edu             |

              =============================================

     In order to maximize the sensitivity for continuum observations

     the GMVA will record at the highest bitrate which instrumentation

     and resources permit. Currently all telescopes will record at 

     4 Gbps (except the KVN, which will record in a compatible 1 Gbps

     mode).  All data will be correlated at the Bonn DiFX software

     correlator.

     * The GBT may be included in GMVA observations if a sufficiently

     compelling justification is given in the proposal but the amount

     of time available will be reduced compared to earlier observing

     semesters, and observing blocks greater than 6 hours will be

     very difficult to schedule.

     ALMA, the KVN and the Greenland Telescope (GLT) can be selected using 

     the "Other Stations" text field in the PST. Rules for requesting the 

     participation of the Mexican LMT in GMVA observations are given 

     in a separate section below.

     Note that the availability of NOEMA (PLATEAU DE BURE) for GMVA

     Session II in 2021 and later sessions is not confirmed. 

     For further details on proposing, including the possibility of

     additional support observations at 7mm (43 GHz), please consult

     the administrative and technical information hosted at the MPIfR:

           http://www3.mpifr-bonn.mpg.de/div/vlbi/globalmm 

The Global mm VLBI Array

www3.mpifr-bonn.mpg.de

Astronomy with Very Long Baseline Interferometry at Millimeter Wavelenghts 

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         PARTICIPATION OF ALMA IN GMVA OBSERVATIONS IN ALMA CYCLE 8

         ==========================================================

     Due to the Corona virus pandemic, ALMA was unable to observe

     together with the GMVA for observations scheduled for GMVA

     Session I in 2020 (ALMA Cycle 7). These observations are now

     re-scheduled for GMVA Session I in 2021.

     ALMA is expected to re-issue a call for proposals for Cycle 8

     in March 2021. Successful proposals will be scheduled in

     GMVA Session I 2022. New GMVA+ALMA proposals for ALMA Cycle 8 must

     be submitted by the GMVA February 2021 deadline, and separately

     to ALMA by the ALMA 2021 deadline.

     GMVA+ALMA proposals which were already submitted to the GMVA in

     February 2020 for ALMA Cycle 8 have been reviewed by

     the GMVA observatories (but not by ALMA) and will be held

     over (with their grades) for possible scheduling in

     GMVA Session I 2022. A separate proposal to ALMA for these projects 

     needs to be submitted following the (new) ALMA Call for

     Cycle 8 proposals in March 2021.  See Cycle 8 pre-announcement at:

       https://almascience.nrao.edu/news/alma-cycle-8-2021-pre-announcement

     Proposers may, instead, submit a revised version of their GMVA+ALMA

     proposal to the GMVA by the February 2021 deadline, 

     which will then be re-evaluated by the GMVA observatories.

     Proposers should give the code number of the earlier proposal

     which is superseded.

     Proposals which have already been submitted will, of course,

     compete with any new GMVA+ALMA proposals submitted at the

     February 2021 deadline.

     Restrictions on GMVA+ALMA proposals in ALMA Cycle 8

     ===================================================

     GMVA observations with ALMA will be limited to a fixed recording

     mode, which currently provides 4 Gbps on all baselines.

     The KVN telescopes will not be available in this mode.

     Only VLBA telescopes will be available at 7mm in this mode.

     Direct phasing up of the ALMA array is limited to sources with a 

     correlated flux density of >500 mJy within an unresolved core on ALMA

     baselines of up to 1 km. Direct phasing-up on the target source

     ("active" phasing) thus limits the strength of the target.

     For weaker sources (<500 mJy), Cycle 8 will introduce the option of 

     "passive" phasing. In this mode, the ALMA array is periodically phased up

     on a bright calibrator source close in angular distance to the

     science target. There will be no restrictions on the flux density of 

     science targets using passive phasing (aside from SNR considerations

     on VLBI baselines). However, the phasing calibrator properties must meet

     the same criteria as for actively phased observations, and it is

     recommended that the calibrator lie within an angular separation of no

     more than 5 degrees from the science target.

     Proposers must specify any such calibrator in their proposal; consult

     the ALMA calibrator catalogue: https://almascience.eso.org/sc/

     In order to make a clean linear-to-circular polarisation

     transformation of ALMA recordings, any target source must be

     observed for a duration of at least 3h (breaks for calibrators

     permitted) to sample a range of parallactic angles.

     Large Programs (>50 hours of observing time) are not permitted

     because phased ALMA is a non-standard mode.

     No long-term programs may be proposed, and no proposals will be

     carried over into the next cycle.

     There is a cap for VLBI of 5% of ALMA Cycle 8 observing time. As

     time for GMVA observations will thus be scarce, proposals should

     include a quantitative justification as to why ALMA is essential

     for the goals of the project.

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        PARTICIPATION OF THE LMT IN GMVA OBSERVATIONS

        =============================================

     The Mexican LARGE MILLIMETER TELESCOPE ALFONSO SERRANO (LMT) may

     be available to participate in some GMVA observations.

     For this a SEPARATE PROPOSAL must be submitted to the LMT

     with a P.I. from the LMT community, as described under

      http://lmtgtm.org/proposal-submission-process/

     Time is allocated to the community as follows:

      - Mexico                      68.25%

      - Uni. Massachusetts Amherst  15%

      - USA (rest)                  15%

      - Spain                        1.75%   (15h per session)

     The P.I. of this LMT proposal need not be the leader (i.e., P.I.) of

     the GMVA proposal, but must agree to take responsibility for all

     necessary arrangements for observing at the LMT, and must be identified

     in the GMVA proposal.

     The proposal should emphasize the value and importance of adding 

     the LMT to the GMVA observations.

     NOTE that the LMT proposal deadline for observations in both

             GMVA  Session II 2021       

      AND    GMVA  Session I  2022

    is in April/May 2021 (i.e. before the August 2021 GMVA proposal deadline).

=============================================================================